I would say unless you are wanting to be a traditional shooter go for the sights, they will make you better, particularly since you are really just getting into it.
As for the release, that is a personal preference. I would say it depends on what bow you are shooting. If your bow is long axle to axle then shooting fingers shouldn't cause any problems and a kisser button will take care of the consistent knocking point. If your bow is shorter axle to axle go with a release. Not only will it improve your accuracy but it will be much more comfortable to shoot.
As for the release, that is a personal preference. I would say it depends on what bow you are shooting. If your bow is long axle to axle then shooting fingers shouldn't cause any problems and a kisser button will take care of the consistent knocking point. If your bow is shorter axle to axle go with a release. Not only will it improve your accuracy but it will be much more comfortable to shoot.